Tea tree oil is obtained from the leaves of Melaleuca alternifolia which is a tree native to a specific area in Australia. It is also called melaleuca oil.

This essential oil has a pale yellow color and smells like camphor. It is often mistaken for tea oil which is a seasoning and cooking oil obtained from tea plants of the genus Camellia.

Tea tree oil was used extensively in the traditional medicine of the indigenous people of eastern Australia. Its use in modern medicine grew after a scientific study identified its antimicrobial properties in the first half of the last century.

However, the introduction of antibiotics reduced the demand for this oil.

Tea tree oil is now once more popular as more people embrace the efficacy and safety of medicinal plants. The tree from which it is obtained is now commercially cultivated, and tea tree oil is currently sold in large quantities.

Other species of Melaleuca from which the oil is now commercially produced are M. dissitiflora and M. linariifolia.

There are over 100 plant chemicals in tea tree oil but the antimicrobial property of the oil is provided by terpinen-4-ol.

Tea tree oil is standardized and sold as the medicinal oil with an ISO number 4730 of 2004 described as Oil of Melaleuca, Terpinen-4-ol type which must contain 15 different plant chemicals in specified amounts.

Composition of Tea Tree Oil

Terpen-4-ol ~ 30-48%

Gamma-terpinene ~ 10-28%

Alpha-terpinene ~ 5-13%

Alpha-terpineol ~ 1.5-8%

Alpha-pinene ~ 1-6%

p-cymene ~ 0.5-8%

Different studies have shown that tea tree oil has more than just cosmetic appeal. When applied on the skin, it acts as antifungal, antibacterial, antiseptic and antiviral agents. The antibacterial property of tea tree oil is potent and demonstrated to be more effective than regular antibiotics for treating resistant bacteria such as MRSA.

The oil is also used to treat scabies, lice, nail diseases, dandruff and yeast infection. Preliminary studies show that it may be effective for treating viral diseases such as cold sores, chicken pox and shingles.

For all its benefits, tea tree oil should only be used topically because it is toxic when ingested.

Topical application of tea tree oil may cause contact dermatitis in a few people. This skin reaction is believed to be triggered by oxidation products of some constituents of tea tree oil on exposure to air and light.

Appropriate dilutions of tea tree oil may be necessary to reduce the chance of developing contact dermatitis.

However, too much dilution can greatly diminish the antimicrobial effects of the oil.

The effectiveness of tea tree oil in acne treatment has been demonstrated by a number of studies. Three of these are discussed below.

A paper published in the British Journal of Dermatology in 2002 by Koh et al. examined the anti-inflammatory effect of tea tree oil. In that study, 27 participants were given intradermal injections of histamine to trigger skin flares and weal.

The result of the study showed that paraffin had no effect on histamine-induced skin inflammation while tea tree oil was effective for reducing the swelling caused histamine.

Given that histamine is a common component of allergic skin reactions, this finding shows that tea tree oil is effective for reducing the swelling mediated by histamine release including the skin inflammation experienced during acne.

In a second study done in 2007 and published in Indian Journal of Dermatology, Venereology and Leprology by Iranian researchers, the efficacy of 5% tea tree oil gel on acne was determined.

In this randomized, double-blind clinical trial, 60 participants with mild to moderate acne were divided into two equal groups. One group was treated with tea tree oil while the other got a placebo. They were then followed up for 45 days and examined every 15 days for total acne lesions and acne severity.

The study result found that 5% tea tree oil was at least 3 times more effective than placebo for reducing the number of acne lesions and about 6 times more effective for reducing the severity of acne.

There are other scientific studies that agree on the effectiveness of tea tree oil in acne therapy.

An even wider study was done by other researchers in the Department of Dermatology of the Royal Prince Albert Hospital in Australia. This study involved 124 participants suffering from mild to moderate acne, and it measured the efficacy of 5% tea tree oil against 5% benzoyl peroxide.

The result showed that both acne medications were effective over the 3 months that the study took.

However, benzoyl peroxide had a faster onset of action but produced side effects in 79% of the participants that it was given to. In contrast, tea tree oil took a little longer to start acting but it produced far less side effects than the peroxide while matching its efficacy over the period of the study.

Acne can be caused by increased colonization of the skin by a harmful strain of Propionibacterium acnes. Another bacterium that is often found on the skin when affected by acne is Staphylococcus epidermis.

When these bacteria invade the skin, they change its nature. They increase the production of sebum and cause an abnormal cycle of inflammation. These changes lead to the formation of superficial and deep acne lesions ranging from pimples and comedones to nodules and cysts.

Tea tree oil can help kill off these acne-causing bacteria. It is particularly useful because these bacteria are becoming increasingly resistant to the regular antibiotics used in acne treatment. Because the chemical composition of the antimicrobial component of tea tree oil differs considerably, it is difficult for these antibiotic-resistant bacteria to develop resistance to it.

This is why tea tree oil is effective against such resilient bacteria like MRSA and why it can treat acne especially where regular antibiotics have failed.

Furthermore, the anti-inflammatory effect of tea tree oil can help reduce the skin inflammation experienced during acne.

Since histamine is a major component of skin inflammations, it is possible that one of the mechanisms by which tea tree oil reduces the severity of acne is through its ability to reduce histamine-induced skin inflammation.

Tea tree oil must never be ingested because it is toxic when taken orally. When applied topically, it should not get in contact with the eyes or any other mucosal membrane.

This sweet-smelling oil is a common ingredient in topical acne products. It is often combined with other botanicals such as witch hazel or conventional acne medications such as benzoyl peroxide.

When supplied in an OTC topical acne product, the oil should be used according to the instructions on the label.

However, you can prepare a tea tree oil gel or cream at home. While there are no standard doses for tea tree oil, it should be diluted to at least 5% strength before use. This dilution can be done with water or any other oil used in skin care.

When diluted with water, 5 (or 1) parts of tea tree oil should be mixed with 95 (or 19) parts of water.

Olive oil, apricot oil and almond oil are some of the oils that can be mixed with tea tree oil. A rule of thumb for diluting with these oils is to mix 2 tablespoons of tea tree oil with ½ cup of the diluting oil. A few drops of tea tree oil can also be mixed with aloe vera gel.

People with sensitive skin types may show allergic reactions to tea tree oil. These reactions will present as blistering, rash and itching.

The oil may aggravate certain skin conditions such as eczema and burns.

To determine if your skin will react to tea tree oil, you can apply a little of the diluted oil to a small part of your skin and see if there will be a skin reaction.